This section provides background information related to the present disclosure which is not necessarily prior art.
Dynamic seals are commonly used in combination with bearings to prevent water and dirt ingress from the outside environment into the bearing. The seal is also used to prevent grease loss from a bearing to the outside. The amount of torque that a seal applies to a rotating shaft system is a parasitic loss that can hinder the system's performance. Therefore, the amount of torque load applied by a dynamic seal is balanced with the seal's capability to adequately perform its sealing function.
Conventional dynamic seal designs have proven to adequately perform the function of preventing water and dirt ingress. However, the conventional dynamic seals can have torque loads of generally 30 pound-inches or larger. The conventional dynamic seals can often require a garter spring to apply added forces to the seal lip which adds torque load as well as added cost to the seal design.
According to one aspect, the present disclosure provides a low or zero friction seal for sealing between a shaft and a bore and includes an inner case adapted to be mounted on the shaft. An outer case is adapted to be mounted within the bore. A seal element is mounted to the inner case and includes a base portion attached to the inner case. A membrane extends from the base portion and a seal lip extends from the membrane and sealingly engages the outer case. As the shaft rotates, the centrifugal forces tend to cause the membrane portion to flex and the torque loads applied by the dynamic seal are reduced to the point that the seal lifts off of the outer case and applies zero torque load.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.